Activate the endogenous Cu2+ switch for Zn(DDC)2 liposomes conversion: Providing a safer and less toxic alternative in cancer therapy.

The ancient anti-alcohol drug disulfiram (DSF) has gained widespread attention for its highly effective anti-tumor effects in cancer treatment. Our previous studies have developed liposome of Cu (DDC)2 to overcome the limitations, like the poor water solubility. However, Cu (DDC)2 liposomes still have shown difficulties in severe hemolytic reactions at high doses and systemic toxicity, which have limited their clinical use. Therefore, this study aims to exploratively investigate the feasibility of using DSF or DDC in combination also can chelate Zn2+ to form zinc diethyldithiocarbamate (Zn (DDC)2). Furthermore, this study prepared stable and homogeneous Zn (DDC)2 liposomes, which were able to be released in the tumor microenvironment (TME). The released Zn (DDC)2 was converted to Cu (DDC)2 with the help of endogenous Cu2+-switch enriched in the TME, which has a higher stability constant compared with Zn (DDC)2. In other words, the Cu2+-switch is activated at the tumor site, completing the conversion of the less cytotoxic Zn (DDC)2 to the more cytotoxic Cu (DDC)2 for effective tumor therapy so that the Zn (DDC)2 liposomes in vivo achieved the comparable therapeutic efficacy and provided a safer alternative to Cu (DDC)2 liposomes in cancer therapy.

Stable Atropine Loaded Film As a Potential Ocular Delivery System For Treatment Of Myopia.

PURPOSE: The objective of the present study was to prepare stable and high bioavailability ocular atropine loaded films (ATR-films) as potential ocular drug delivery systems for the treatment of myopia. METHODS: ATR-films were prepared by the solvent casting method and the physical properties of films were evaluated including thickness, water content, light transparency, disintegration time, and mechanical properties. FT-IR, DSC, XRD, TGA, AFM, and Raman spectroscopy were performed to characterize the film. The stability test was conducted under different conditions, such as high humidity, high temperature, and strong light. The pharmacokinetic study and irritation assessment were conducted in rabbits. The efficacy of ATR-films was evaluated by refraction and ocular biometry in myopia guinea pigs. RESULT: After optimizing the formulation, the resulting ATR-film was flexible and transparent with lower water content (8.43% ± 1.25). As expected, the ATR-film was stable and hydrolysate was not detected, while the content of hydrolysate in ATR eye drops can reach up to 8.1867% (limit: < 0.2%) in the stability study. The safety assessment both in vitro and in vivo confirmed that the ATR-film was biocompatible. Moreover, the bioavailability (conjunctiva 3.21-fold, cornea 2.87-fold, retina 1.35-fold, sclera 2.05-fold) was greatly improved compared with the ATR eye drops in vivo pharmacokinetic study. The pharmacodynamic study results showed that the ATR-film can slow the progress of form-deprivation myopia (~ 100 ± 0.81D), indicating that it has a certain therapeutic effect on form-deprivation myopia. CONCLUSION: The ATR-film with good stability and high bioavailability will have great potential for the treatment of myopia.

Asymmetric Total Synthesis and Biosynthetic Implications of Perovskones, Hydrangenone, and Hydrangenone B.

Perovskones and hydrangenones are a family of structurally complex triterpenoids that were mainly isolated from the genus Salvia medicinal plants. These isoprenoids exhibit a broad range of biological activities, such as antitumor and antiplasmodial activities. Here, we report the collective total synthesis of perovskone, perovskones C, D, F, hydrangenone, and hydrangenone B. The key strategies in this work include the following: (1) an asymmetric photoenolization/Diels-Alder reaction was developed to construct a tricyclic ring bearing three contiguous quaternary centers, which was used to build the core icetexane skeleton; (2) a bioinspired Diels-Alder reaction of perovskatone D with trans-α-ocimene was applied to stereospecifically generate perovskones; (3) late-stage oxidations and ring forming steps were developed to synthesize perovskones and hydrangenones. Our synthetic work suggests that (1) perovskatone D may serve as the precursor of the biosynthesis of perovskones and (2) the formation of hydrangenone and hydrangenone B, containing a five-membered D ring, may involve an oxidative ring cleavage and ring regeneration process.

Toxicity Reduction and Efficacy Promotion of Doxorubicin in the Treatment of Breast Tumors Assisted by Enhanced Oral Absorption of Curcumin-Loaded Lipid-Polyester Mixed Nanoparticles.

Curcumin (CUR), a polyphenol derived from turmeric, exhibits anticancer and anti-inflammatory properties. However, it has poor water solubility, stability, and oral bioavailability. To overcome these limitations, lipid-polyester mixed nanoparticles (NPs) embedded in enteric polymer-EudragitL100-55(Eu) were formulated (CUR-NPs-Eu). NPs composed of mPEG-b-PCL have a hybrid core made up of middle chain triglyceride (MCT) and poly(ε-caprolactone) (PCL) for enhancing drug loading. The CUR-NPs with MCT content of 10% had a particle size of 121.2 ± 16.8 nm, ζ potential of -16.25 ± 1.38 mV, drug loading of 9.8%, and encapsulation efficiency of 87.4%. The transport of the CUR-NPs-Eu across Caco-2 monolayers is enhanced compared with CUR alone (1.98 ± 0.94 × 10-6 of curcumin versus 55.43 ± 6.06 × 10-6 cm/s of curcumin-loaded NPs) because of the non-disassociated nanostructure during absorption. The absolute bioavailability of CUR-NPs-Eu was 7.14%, which was drastically improved from 1.08% of the CUR suspension (CUR-Sus). Therefore, in the xenograft 4T1 tumor-bearing mice, increased drug accumulation in heart and tumor was noticed because of enhanced oral bioavailability of CUR. The chemosensitizing effect of CUR was attributed to its NF-κB reduction effect (148 ± 11.83 of DOX alone versus 104 ± 8.71 of combined therapy, ng/g tissue). The cardioprotective effect of CUR was associated with maintenance of cardiac antioxidant enzyme activity and down-regulation of NF-κB. This study provided a partial illustration of the mechanisms of chemosensitizing and cardioprotective effects of CUR utilizing the oral availability promotion effect brought by the NPs-Eu formulation. And these results further demonstrated that the capability of this NPs-Eu system in oral delivery of poorly soluble and poorly permeable drugs.

Pharmaceutical strategies of improving oral systemic bioavailability of curcumin for clinical application.

Curcumin (Cur), a natural compound from Curcuma longa Linn, has various of pharmacological activities such as anti-cancer, anti-inflammatory, anti-oxidant, anti-Alzheimer, anti-microbial and more. Curcumin also has nephroprotective, hepatoprotective, neuroprotective, antirheumatic and cardioprotective effects. However, its low aqueous solubility inhibits the oral bioavailability of curcumin. As well, curcumin can be metabolized rapidly by intestinal tract which can also result in low oral bioavailability. In fact, the bioavailability of curcumin is low even through intraveneous administration routes. Various of pharmaceutical strategies for oral administration including solid dispersions, nano/microparticles, polymeric micelles, nanosuspensions, lipid-based nanocarriers, cyclodextrins, conjugates, polymorphs have been developed in order to improve the oral bioavailability of curcumin. These pharmaceutical strategies can increase the solubility of curcumin, improve the intestinal stability of curcumin, change the absorption route of curcumin and allow for coadministration with other adjuvants. Here we discuss efficacy studies in vitro and in vivo of curcumin nanoformulations, as well as human clinical trials.

A Comprehensive Preclinical Evaluation of Intravenous Etoposide Lipid Emulsion.

PURPOSE: Etoposide is one of the principal chemotherapeutic agents used for the treatment of small cell lung cancer (SCLC). There are some disadvantages of currently available etoposide injections (EI) such as low LD50, necessary dilution before clinical application, thus, etoposide lipid emulsion (ELE) was developed and expected to have a comparable or better effect on SCLC. METHODS: ELE was prepared through high-pressure homogenization method, and a series of evaluations such as encapsulation efficiency (EE%), in vitro release, stability studies, pharmacokinetics study, safety assessment and pharmacodynamic study were systematically performed. RESULTS: ELE had high EE% and good stability. Pharmacokinetics study revealed ELE had a longer T1/2 F compared with EI, which is in agreement with in vitro release in which ELE released slower than EI (EI released over 80% within 12 h, while ELE released 50%). Safety tests showed there was no hematology or significant tendency of accumulated toxicity, and LD50 of ELE was higher than EI. Furthermore, percentage of tumor inhibition (TI%) of ELE was comparable with EI in the same dose. CONCLUSIONS: Unlike EI, ELE could further increase the dose, which endowed etoposide with a greater potential for cytotoxic agent. LE is a promising delivery system for etoposide.

Biopharmaceutical characters and bioavailability improving strategies of ginsenosides.

Deglycosylation is the most important gastrointestinal metabolism in which ginsenosides are split off from glycosyl moieties by the enzymes secreted from intestinal microflora, and two possible metabolic pathways of protopanaxdiol-type ginsenosides (PPD-type ginsenosides) and protopanaxtriol-type ginsenosides (PPT-type ginsenosides) have been concluded. The former is deglycosylated at C-3 and/or C-20, and transformed to protopanaxdiol (PPD). By comparison, the latter is deglycosylated at C-6 and/or C-20, and eventually transformed to protopanaxtriol (PPT) instead. The pharmacokinetic behavior of PPD-type ginsenosides and PPT-type ginsenosides is different, mainly in a faster absorption and elimination rate of PPT-type ginsenosides, but almost all of ginsenosides have a low oral bioavailability, which is relevant to the properties, the stability in the gastrointestinal tract, membrane permeability and the intestinal and hepatic first-pass effect of ginsenosides. Fortunately, its bioavailability can be improved by means of pharmaceutical strategies, including nanoparticles, liposomes, emulsions, micelles, etc. These drug delivery systems can significantly increase the bioavailability of ginsenosides, as well as controlling or targeting drug release. Ginsenosides are widely used in the treatment of various diseases, the most famous one is the Shen Yi capsule, which is the world's first clinical application of tumor neovascularization inhibitors. Hence, this article aims to draw people's attention on ocotillol-type ginsenosides, which have prominent anti-Alzheimer's disease activity, but have been overlooked previously, such as its representative compound-Pseudoginsenoside F11(PF11), and then provide a reference for the druggability and further developments of ocotillol-type ginsenosides by utilizing the homogeneous structure between dammarane-type ginsenosides and ocotillol-type ginsenosides.

Evaluating the safety of phytosterols removed perilla seed oil-based lipid emulsion.

OBJECTIVES: The aim of this study was to ascertain the potential toxicity of perilla seed oil-based lipid emulsion (POLE) caused by phytosterols and confirm the efficacy of the technique for removing phytosterols from perilla seed oil, and evaluate the safety of a low phytosterol POLE in a long-term tolerance study in dogs. METHODS: A comparison between a soybean oil lipid emulsion (Intralipid group A) and POLE with high (group B) versus low (group C) levels of phytosterols was made with regard to their effects on the general condition, hematological and biochemical parameters, urinalysis and histopathological changes in nine dogs receiving daily infusions for four weeks at dosage levels of 6, 6, 9 g fat /kg. RESULTS: Dogs in group A and group C remained in good condition and gained weight during the infusion period and no diarrhea or gastrointestinal bleeding occurred. Only a moderate degree of anemia was observed, the biochemical parameters changed only slightly and returned to normal after treatment had ceased. However, the dogs in group B exhibited significant symptoms of 'fat overload syndrome'. Vomiting, diarrhoea and blood in the faeces were observed. Moreover, triglyceridemia, cholesteremia, and dark urine as well as microscopic signs of liver and gastrointestinal tract damage and generalized jaundice were clearly seen. CONCLUSIONS: Phytosterols promote 'fat overload syndrome' in long-term tolerance studies of POLE in dogs by producing cholestatic liver injury and interfering with fat metabolism. And the toxicity of POLE was reduced by removing phytosterols.

Preclinical evaluations of norcantharidin-loaded intravenous lipid microspheres with low toxicity.

OBJECTIVES: The aim of this study was to perform a systematic preclinical evaluation of norcantharidin (NCTD)-loaded intravenous lipid microspheres (NLM). RESEARCH DESIGN AND METHODS: Pharmacokinetics, biodistribution, antitumor efficacy and drug safety assessment (including acute toxicity, subchronic toxicity, hemolysis testing, intravenous stimulation and injection anaphylaxis) of NLM were carried out in comparison with the commercial product disodium norcantharidate injection (NI). RESULTS: The pharmacokinetics of NLM in rats was similar to that of NI, and a non-linear correlation was observed between AUC and dose. A comparable antitumor efficacy of NLM and NI was observed in mice inoculated with A549, BEL7402 and BCAP-37 cell lines. It was worth noting that the NLM produced a lower drug concentration in heart compared with NI, and significantly reduced the cardiac and renal toxicity. The LD(50) of NLM was twice higher than that of NI. In NLM, over 80% of NCTD was loaded in the lipid phase or bound with phospholipids. Thus, NCTD was sequestered by direct contacting with body fluids and largely avoided distribution into tissues, consequently leading to significantly reduced cardiac and renal toxicity. CONCLUSIONS: These preclinical results suggested that NLM could be a useful potential carrier for parenteral administration of NCTD, while providing a superior safety profile.

Evaluation of submicron emulsion as vehicles for rapid-onset intranasal delivery and improvement in brain targeting of zolmitriptan.

This study was to evaluate submicron emulsion as a drug carrier for intranasal delivery of zolmitriptan (ZT). Since the drug distribution in submicron emulsion might influence the nasal absorption, two different formulations separately incorporating the drug in oily phase (ZTSE-1) and aqueous phase (ZTSE-2) were assessed. To find the better formulation for rapid-onset intranasal delivery and improvement in brain targeting of ZT, the in vivo nasal absorption of these two formulations was evaluated. The blood and cerebrospinalfluid (CSF) pharmacokinetics of ZTSE-1, ZTSE-2 and ZT solution (ZTS) were evaluated after intranasal administered to anesthetized Wistar rats. The results demonstrated that ZT from ZTSE-1 and ZTSE-2 had better brain targeting efficiency than the ZTS. In plasma and CSF, the ZTSE-2 reached peak concentration much faster than ZTSE-1 and ZTS. The ZTSE-2 also presented significantly higher initial ZT levels in CSF compared with the ZTSE-1 and ZTS. The results indicated that incorporation of ZT in the aqueous phase of submicron emulsion was effective for rapid intranasal delivery of drug to blood and brain, which would offer patients the benefits of rapid relief from migraine.

Evaluation of the efficacy, toxicity and safety of vinorelbine incorporated in a lipid emulsion.

To reduce the severe adverse effects of vinorelbine (VRB) with the aim of improving patient compliance, a parenteral vinorelbine-loaded lipid emulsion (VLE) has been developed. The objective of the present study was to get insight into the preclinical antitumor efficacy, toxicity and safety of VLE, and compare this with that of the commercial product, Navelbine(®) i.v. (VS). Comparable antitumor efficacy of VLE and VS was observed in tumor-bearing nude mouse models inoculated with A549 human lung cancer, hepatoma solidity (Heps) G2 cancer and BCAP-37 human breast cancer cells. The median lethal dose (LD(50)) in mice was 29.3mg/kg (male) and 32.1mg/kg (female) for VLE, while the corresponding value was 30.5mg/kg (male and female) for VS. In the long-term toxicity study, VLE significantly reduced the decreases in RBC, HC, WBC and WBC differential count (DC) levels. Lesions in spleen, thymus, lymph nodes, bone marrow, testis, ovary and injection site induced by VS were much more severe compared with VLE. VLE also exhibited less local venous irritation than VS, as well as no hemolysis or hypersensitivity. Consequently, these observations clearly indicate that the lipid emulsion could be a useful potential parenteral carrier for VRB with equivalent efficacy and lower toxicity.

In vitro and in vivo evaluation of fenofibrate solid dispersion prepared by hot-melt extrusion.

OBJECTIVE: This article aimed to develop fenofibrate solid dispersion with high bioavailability using hot-melt extrusion and compare the difference of Eudragit E100 and polyvinylpyrrolidone-vinyl acetate copolymer S630 (PVP-VA) in dissolution. METHODS: Solid dispersion with carrier of Eudragit E100 or PVP-VA was prepared by hot-melt extrusion and then characterized by differential scanning calorimetry (DSC), X-ray diffraction, in vitro dissolution test, and in vivo bioavailability study. RESULTS: Fenofibrate exited as noncrystal state in these two kinds of solid dispersions that can be proved by DSC and X-ray diffraction. Eudragit E100 1:2 solid dispersion has the dissolution of 84% and 65% at 60 minutes in 0.1M HCl and water, respectively. Eudragit E100 1:4 solid dispersion has lower dissolution in 0.1M HCl and higher dissolution in water; the values are 73.6% and 87.3%. PVP-VA 1:2 solid dispersion has the dissolution of 60% and 65% at 60 minutes in 0.1M HCl and water, respectively. PVP-VA 1:4 solid dispersion has higher dissolution in 0.1M HCl and lower dissolution in water; the values are 64% and 53%. The different dissolution of fenofibrate from the two polymers is because of their different solubility and gelling tendency. When Eudragit E100 1:4 solid dispersion was administrated to beagle dogs, its relative bioavailability to micronization Lipanthyl capsule was 177.1%. CONCLUSION: Hot-melt extrusion is an excellent method to improve the dissolution and therefore the bioavailability of fenofibrate.

[Preparation and in vitro and in vivo evaluation of etoposide submicro-emulsion for intravenous injection].

The aim of this thesis is to prepare etoposide submicro-emulsion (ESE) for intravenous injection and investigate its characteristics in vitro and in vivo. High-pressure homogenization was used to prepare ESE, using 10% (w/w) soybean oil and 10% (w/w) medium-chain triglyceride as mixed oil phase, and 1.8% (w/w) fabaceous lecithin as emulsifier. The pH was adjusted to 5.5 with 0.1 mol x L(-1) NaOH to keep the most stability of ESE. The particle size distribution and zeta potential were measured using photon correlation spectroscopy. Ultrafiltration was used to estimate the relative percentages of etoposide in each phase. Long-term storage test and accelerated isothermal test-Weibull distribution method were used to estimate the physical and chemical stability of ESE. Plasma pharmacokinetics in rats was monitored by high performance liquid chromatography by comparison with etoposide nonaqueous solution at the same time. The mean particle size, zeta potential and entrapment efficiency of ESE were (189.9 +/- 54.6) nm, - 32.6 mV and 91.7%, respectively. The emulsion was stable during 9 month storage at 4 degrees C. The shelf life (T0.9) of etoposide in lipid emulsion was estimated to be about 665 days at 4 degrees C. The drug concentration-time curves of ESE and solution were similar and could be described by two compartment model. The area under the curve of concentration versus time from zero to the last time point and the mean residence time of ESE and solution were (18.30 +/- 8.74) and (19.32 +/- 6.45) microg x h x mL(-1), and (1.46 +/- 0.32) and (1.71 +/- 0.52) h, respectively. Etoposide was incorporated in submicro-emulsion to improve its physical and chemical stability without addition of organic solvents with insignificant different characteristics in vivo when compared with solution.